88 IROC smokes after idling a few minutes..

09-16-2009, 10:58 PM
1988 5.7 TPI IROC Auto

sorry, long

As the title states, If I let the car sit and run it smokes after a minute or so. I am not sure what the issue is. It no longer smokes on startup since I replaced the injectors. It is a blueish looking smoke. Hard to tell. Doesn't smell like oil, doesn't look like oil smoke. Smells rich but not like raw gas.

The engine is a stock replacement and has less than 15K miles on it. All compression is in spec. Does not use oil, oil still stays fairly clean in between changes. Vacuum is 18" hg. Complete tune up is about 1.5 years old. The fuel injectors are new and flowmatched.

The only oustanding issues with the car are that the O2 sensor make be going out as it seems to read lean on my air/fuel guage. It is an NTK (NGK) and is about 1.5 years old. The other is that EGR valve is new but solenoid is not hooked up correctly right now. basically vacuum lines and connector plugged in, but not mounted under the coil and I believe it is self grounding.

Can EGR cause a smoking issue?

09-17-2009, 11:33 AM
If I recall correctly, blue-ish smoke indicates gas in your oil. If I'm right you can tell by checking the dip stick, and with your fingers do as if you would with a rag to clean the oil off it. Now, if there's gas in your oil you should be able to see the gas run off your fingers or you could even smell it on the oil.

09-17-2009, 08:39 PM
Appreciate the response. The oil is new. I did think it possible that my old injectors could be letting fuel leak into the crankcase when the engine was off. The old injectors were shot! Anything else to check? You think EGR could cause it?

09-18-2009, 03:54 AM
Correct me if I'm wrong but the egr when its shot....is shot. So I don't think its just that. Ok this is what I would do in your case..... work yourself back from the egr, you know... if you think its the egr, try and check the plugs to the thing, or maybe it has a loose end somewhere you know. then again it could just be crap that somehow got there when the motor was being installed and now its burning it off, hey that's an optimistic way of looking at it.

09-19-2009, 03:45 PM
Cool, Looks like that is what I am going to have to do, the Solenoid and valve are new, but like I said the solenoid is hooked up right, It is a hassle to remove the coil and mount and I haven't had time, but I will start there and work my way back to checking compression again. Thanks for the response.

09-25-2009, 11:23 PM
Well, I reran every test I am capable of which is all but one, fuel pressure
so I have a new fuel pressure testor and a scan tool that reads live engine data coming so I can see why the car seems lean, hopefully that fixes the smoke too.

10-13-2009, 09:34 PM
It was the computer. Sensors ran fine at the sensor; live data on the scanner showed that the computer was not showing the correct readings. Now it has awseome power and no more smoke.

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